<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        div {
            width: 100px;
            height: 100px;
            margin: 100px auto;
        }

        input {}
    </style>
</head>

<body>
    <div>
        <input type="text" name="" id="">
    </div>

    <script>
        var input = document.querySelector('input');

        document.addEventListener('keyup', function (e) {
            console.log(e.keyCode);
            if (e.keyCode == 83) {
                // console.log(1);
                input.focus();
            }
        })
    </script>
</body>

</html>